Effects of Sc and Zr on microstructure and properties of 1420 aluminum alloy

Effects of Sc and Zr on microstructure and properties of 1420 aluminum alloy were investigated. With the additions of Sc and Zr, the coarse primary Al3(Sc,Zr) particles formed at the solidification process were difficult to be dissolved into the matrix during homogenization. The precipitations of Al3Li and Al3Li/Al3(Sc,Zr) occurred during aging process. The growth rates of Al3Li and δ′-PFZs were retarded with the additions of Sc and Zr. The mechanical properties were significantly improved with the additions of Sc and Zr. The mechanical properties (UTS = 300 MPa, YS = 211 MPa and EL = 6.8%) were obtained in 1420-Sc-Zr alloy aged at 190 °C for 16 h. Moreover, the thermal diffusivity and corrosion resistance were significantly affected with the additions of Sc and Zr. With the additions of Sc and Zr, the thermal diffusivity was efficiently increased by 28% during aging process, however, the corrosion resistance decreased.